Diagnostic Criteria: Essential Thrombocythemia
| I. Platelet count >600,000/μL |
| II. Hematocrit <40, or normal RBC mass (males <36 mL/kg, females <32 mL/kg) |
| III. Stainable iron in marrow or normal serum ferritin or normal RBC mean corpuscular volume* |
| IV. No Philadelphia chromosome or bcr/abl gene rearrangement |
| V. Collagen fibrosis of marrow |
| A. Absent or |
| B. < of biopsy involved and neither marked splenomegaly nor a leukoerythroblastic reaction |
| VI. No cytogenetic or morphologic evidence for a myelodysplastic syndrome |
| VII. No cause for reactive thrombocytosis |
| I. Platelet count >600,000/μL |
| II. Hematocrit <40, or normal RBC mass (males <36 mL/kg, females <32 mL/kg) |
| III. Stainable iron in marrow or normal serum ferritin or normal RBC mean corpuscular volume* |
| IV. No Philadelphia chromosome or bcr/abl gene rearrangement |
| V. Collagen fibrosis of marrow |
| A. Absent or |
| B. < of biopsy involved and neither marked splenomegaly nor a leukoerythroblastic reaction |
| VI. No cytogenetic or morphologic evidence for a myelodysplastic syndrome |
| VII. No cause for reactive thrombocytosis |
If these measurements suggest iron deficiency, PV cannot be excluded unless a trial of iron therapy fails to increase the RBC mass into the polycythemic range.
Modified and reprinted with permission.12